[04MACHI]

Got a Mach completly stock.
I would like to gain some horsepower but not under the hood
(YET, No funds for that for now)
also in my mind is, less weight is more power in a way...
So, I am thinking those 3 aditives;

aluminum pulleys.
aluminum transmission.
change in rear gear.

Are all 3 good to do, and how much would they
add to my horses? Any good recomendations for
any of those? Which rear gear?
And is a alum drivetrain reliable?

Second issue.
What can I do to lean my mixture a bit?
put spacers on the oxigensensors?
I want to test something, if it works I'll
share the knowledge.
Any info on leaning it out is welcome.

(I know the consequeses, but it is only
for a short test period, about a week)

 

[dollarbill]

Alluminum underdrive pullies will free up some hp and mpg. I had the BBK ones on my 97gt and as my first mod I swear I could feel the difference. I have never heard about swapping to an aluminum trans. I have heard of aluminum driveshaft, but I haven't ever seen a before and after dyno comparison to back up any claims. I'm pretty sure the case on both the auto and 5 speed are aluminum anyways. Yes a change in rear gears can help mpg. I recemond 3.73, or 4.10, some companies beside FRPP make a 3.90 as well. A custom dyno tune with a tuner will optimize your combo and give more efficient performance. A K&n stlye filter or complete cold air induction kit will also help.

 

[Trentonso]

Actually a change in rear gears to a higher number will decrease MPG as the engine rpms will be higher at highway speeds. Think of it as driving in 4th gear for 100 miles versus using 5th, although a gear swap will not be as drastic. It will be more likely around 500 rpms difference, depending on the gear ratio you select.

 

[dollarbill]

Your wrong. Higher numericaly gears put the engine in a more efficient powerband. Being in this higher powerband the engine works less and is more efficient. Now I'm not saying go out and get some 4.56s and tool down the highway at 3K rpm. I can only speak from my personal expierience. My 97 gt had 3.73s, underdrives, exhaust, and some other bolt ons. I easily got 26 mpg with the a/c blowing going 75 mph on more than 1 occasion. If your thereoy is correct why doesn't Ford go back to 2.73s to avoid the gas gussler tax? With the stock gears at highway speeds the engine is somewhat bogged down and not operating in its most effecient range.

 

[04MACHI]

yeah, thats what I meant, aluminum driveshaft.
I dont think the stock shaft is aluminum...
I looked in to carbon fiber and aluminum,
they both seem to handle 600hp and up.
but prices in both vary dramatically. Thats
why I'll stick with the aluminum one.
If it would make enough difference in weight at least.